Generally,“presence” is the concept of providing others with information about a user's ability or willingness to communicate. In the prior art, the concept of using presence in communication systems is often applied in instant messaging systems. Presence is also used in other network communication systems, such as the Microsoft Unified Communication Service. However, these prior art systems rely on a connection to a computer network to deliver presence information.
In many situations, a caller attempts to call someone using the standard public switched telephone network or a cellular network. In the prior art, such a caller has only limited information about who is available to take a call, or their willingness to take it. The caller may not have the proper equipment to connect to a network presence server, or a network presence server may not be available, or the person being called may not have a connection to a computer network to take advantage of networked presence servers. Currently, when a caller makes a call over a cellular or landline telephone network, either the call is answered by somebody, the line is busy, no one answers the call, or an answering machine/voice mail answers the call.
As a result, there is a need for improved methods and apparatuses for delivery of presence information over cellular and landline telephone networks.